Heat Shields?
 

I was wondering if the heat shield on the Headers of a 1st gen protege, if they were removed maybe help ventilate the lower part of the engine better,I was also wondering, my car is eating gas like crazy right now, it was fine on gas until I put the Mushroom filter on and this cold cold weather hit anyideas on any of these questions, i was wondering if maybe the filter was more restrictive than the otehr?

concerning fuel economy, check the following.....

1. BOSCH Platinum Spark Plugs....check the gap, also ask if anyone
else has had experience with these plugs in a Mazda. I put
them in a V6 GM and it would hardly run. Had to replace with Delco.
I have the NGK V-power BKR5E-11 in my Protege, as soon as I put them
in, there was less engine noise. Haynes says the 92 takes the same plug or
a the NGK BKR6E11.

2. Check the Emission System, good canidate would be Oxygen Sensor,
PCV valve, and Air flow meter. The O2 sensor instructs the ECU as to the
correct fuel air mixture. The O2 sensor has to be over 600f to operate at all.
I wonder if a missing heat shield would effect this and/or extremely low temps?
Without input from the O2 sensor the ECU defaults to a fixed fuel setting
resulting in poor economy. Check that you have a good connection to the O2
sensor as well.

3. Easy things to improve fuel economy such as driving conditions, driving
habits, and tire pressure. The less tire surface in contact with the road
the less friction to overcome. Also, worn tires could be result of poor
alignment which actually restrict forward motion.

Best regards

Thanks, sorry for my l;ate reply i never saw that someone responded...

The heat shield on the exhaust manifold is necessary unless you get your shit ceramic coated.
But thats a waste of money on a stock manifold except for bling maybe.
Use NGK copper plugs.
The cold weather usually kills fuel economy to a certain extent. But make sure everything is running right, you can check the plugs, wires, cap rotor etc..........